# Tag Info

But I can't figure out what the type should be for the denotation for identifiers. That is because you are implicitly tracing the denotation function $⟦\_⟧$. It might get easier to see the type if you explicitly trace the denotation function by tagging them appropriately. $⟦x + y⟧_{AExp}\sigma = ⟦x⟧_{AExp}\sigma + ⟦y⟧_{AExp}\sigma$. Similarly, if you ...